|United States Patent||5,909,686|
|Muller , et al.||June 1, 1999|
A method and apparatus for providing hardware-assisted CPU access to a forwarding database is described. According to one aspect of the present invention, a switch fabric provides access to a forwarding database on behalf of a processor. The switch fabric includes a memory access interface configured to arbitrate access to a forwarding database memory. The switch fabric also includes a search engine coupled to the memory access interface and to multiple input ports. The search engine is configured to schedule and perform accesses to the forwarding database memory and to transfer forwarding decisions retrieved therefrom to the input ports. The switch fabric further includes command execution logic that is configured to interface with the processor for performing forwarding database accesses requested by the processor. According to another aspect of the invention one or more commands are provided to implement the following functions: (1) learning a supplied address; (2) reading associated data corresponding to a supplied search key; (3) aging forwarding database entries; (4) invalidating entries; (5) accessing mask data, such as mask data that may be stored in a mask per bit (MPB) content addressable memory (CAM), corresponding to a particular search key; (6) replacing forwarding database entries; and (7) accessing entries in the forwarding database.
|Inventors:||Muller; Shimon (Sunnyvale, CA), Hendel; Ariel (Cupertino, CA), Yeung; Louise (San Carlos, CA), Hejza; Leo (Sunnyvale, CA), Murthy; Shree (Sunnyvale, CA)|
Sun Microsystems, Inc.
|Filed:||June 30, 1997|
|Current U.S. Class:||1/1 ; 370/224; 370/400; 370/401; 370/402; 707/999.001; 707/999.104; 707/999.107; 707/E17.005|
|Current International Class:||G06F 17/30 (20060101); G06F 017/30 ()|
|Field of Search:||707/1,104 370/400,401,402,229 395/200.47,200.48,200.49|
|5309437||May 1994||Perlman et al.|
|5459717||October 1995||Mullan et al.|
|5485455||January 1996||Dobbins et al.|
|5500860||March 1996||Perlman et al.|
|5790456||August 1998||Dobbins et al.|
"Foundry Products", downloaded from Website http://www.foundrynet.com/ on Jun. 19, 1997. .
Anthony J. McAuley & Paul Francis, "Fast Routing Table Lookup Using CAMs", IEEE, 1993, pp. 1382-1390. .
"Gigabit Ethernet", Network Strategy Report, The Burton Group, v2, May 8, 1997 40 pages. .
"IP On Speed", Erica Roberts, Internet-Draft, Data Communications on the Web, Mar. 1997, 12 pages. .
"Multilayer Topology", White Paper, Internet-Draft, 13 pages, downloaded from Website http://www.baynetworks.com on Apr. 18, 1997..